The most practical shotguns are the TM kind or anything that uses the 3-shot burst, shell magazine.
The shell holds 30 BB's and the gun is spring operated; no gas or batteries. You rack it for every shot and you get 10 x 3-shot bursts. Research some Youtube video's of these.
Obvious disadvantage is less ammo and rate of fire. But it's a more solid platform and you know how the gun is going to behave (which ironically is not to shotgun-y). The range and grouping is also impressively tight with TM shotguns.
Overall, shotguns are most badass too that's why you want one. I mean come on, shotguns are the trademark of 'macho' in with firearms.